Process of refining crude asphaltum



(Specimens.)

15b` ALEXANDER. raocss: oP-'RBHNING :ORUDEMPHALTUM No. 435,198.

Patented Aug. 26, M390.

City, in the county VNew Jersey, have invented certain new and UNITED STATES PATENT OFFICE.

ROBERT ALEXANDER, OF JERSEY CITY,.-NE \V JERSEY.

PROCESS OF REFINING CRUDE ASPHALTUM.

SPECIFICATION forming part of Letters Patent No. 435,198, dated August 2e, 189e.

I Application filed January 8,1890. No. 336,288.v (Specimens.)

To all whom it may'concern;

' Be it known that I, ROBERT ALEXANDER, a citizen of the United States, residing at Jersey of Hudson and State of useful Improvements in Refining Crude Asphaltum; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to 4make and use the same.

Prior to my invention it hasbeen custom ary te effect the desiccation and liquefaction of'native asphaltum (Trinidad and the like) by placing it in vessels prepared for the purpose and subjecting it therein to external heat during a periodof four or five days, at a temperature ranging betwen 400 and 500o Fahrenheit. This long period of exposure to the comparatively high heat referred to has heretofore been found necessary in order to drive off completely the water present in the native material and to fully melt said material or bring it to a 'homogeneous liquid condition. In many instances, however, it has been found impossible, even at the end of four or five days, to entirely liquefy the mass of crude material. The central portion of the charge, being relatively distant from the heated Walls of the containing-vessel, does not always receive a suicient amount of heat to be melted, and frequently remains as an unreduced core after the outer portions are -desiccated and liquefied. Under such circumstances it is impraeticable to vraise the furnace heat so as to reduce the said coro, for the reason that the higher heat that would be necessary for that purpose would burn or destructively distill the material already melted. It has therefore beenfound necessary in these instances to interrupt the operation and tap -oi the melted portion, the unreduced core remaining in the containingvessel and the space around it being thereupon filled in with fresh material for a sub.-

sequent melting. It is manifest that when this unreduced core is present the effective melting capacity of the vessel is materially diminished and the product of the operation 5o proportionally decreased.

One of the objects of my invention is to more uniformly vdistribute the heat through-l out the charge during the entire operation, thereby lessening its d-ration and preventing the formation of a core.

The treatment to which the desiecated product has been subject-edv has deprived it in petroleum is added when the desiccatcd ma-` terial is in a melted condition, and the melting-temperature is maintained until the most intimate -admixture of the two is secured, the crude petroleum serving as a solvent or diluent. Experience has shown, however, that the addition of this crude petroleum causes the desiccated material when laid as a pavement to begin to disintegrate or rot Within a comparatively short time.

I have discovered that this disintegration is due to the presence of the crude petroleum and to the absenceof the asphaltum oils driven off during the melting operation, and is diminished in proportion as the original percentage of those oils is restored to the desiccated material, of which they form the material and appropriate solvent. I have accordingly adopted means for recovering the greater portion of said oils dll-ring the melting opera-tion as condensable by-produ`cts of the manufacture, for the purpose of returning them thereafterpto the desiccated material, so as to diminish or entirely supplant the `crude petroleum. In order, however, to retain as many ofthe said oils as possible in the desiccated material during the operation, and in order to prevent material' destructive distillation of the remainder, I employ a procedure enabling me to conduct the dcsiccation and liquefaction at a comparativel y low temperature, so that those oils only which are volatile at or below such temperature shall be given olf to the condenser.

The entire volatile products, consisting of watery. vapors, asphaltum-oil vapors, small IOO condensable gases as are inseparable from the operation, are received in an appropriate condensing and separating vessel, whence the condensable matters pass to a convenient receptacle, while they combustible gases are led into the fire-place and burned therein. As a consequence, the operation is quite devoid of noxious or deleterious matters prejudicial to public health or comfort and may be practiced without restriction from local authorities.

In the accompanying drawings, Figure 1 represents in vertical section and partial elevation a form of apparatus appropriate to my invention, and'Fig. 2 represents a like view, on an enlarged scale, of certain details thereof.

Similarnumerals of reference indicate similar parts in both figures."

Referring to the drawings, 3 indicates a suitable furnace provided with the usual adj uncts for supplying and maintaing an effective heat therein. Upon the fire-arches, as shown, rests the melting or desiccating vessel, consisting, preferably, o f the lower cylindrical portion 4 and the hood or cap 5, adapted to be firmly andsecurely bolted thereto. Danger of explosion is prevented by means of the safety- 'alve device 6, mounted upon the short pipe 7, connected to the top plate of the hood 5 andcommunicating freely with the interior of the desiccating-vessel. A pipe 8 comuninicates with the pipe 7, and is also connected by means of the jointcoupling 9 with the descending pipe 10,1eading to the condenser and separator 11. "lhe joint-coupling 9 is provided with a suitable screwdown valve 12, whereby the outer or proximate end of the pipe 8 may be closed when desired. 'lhe condenser and separator 11 is of a familiar type, consisting of a main body portion, a curved entrance branch 13, and an upwardly extended pipe 14, forming a continuation of the pipe 15. A glass gage 16 indicates the height of liquid within condenser, and a draw-off pipe 17, having a stop-cock 18, serves to conduct the liquid condensates to the discharge 19, opening into the receptacle 20. The pipe 15 communicates by a stop-cock coupling 21 with the pipe 19 and with the gas-discharge pipe 22, opening into the furnace. Air under pressure is supplied to the desiccating-vessel by means of the pipe 23, having the screw-- down valve 24. 'lhe pipe 23 entendsinwardly to the center of the vessel and then downwardly by the descending pipe 25 to the lower part thereof, where it communicates with horizontalbranch pipes 26, provided with a' series of bottom perforations, as shown.

The operation of the invention is as follows: The crude or native Trinidad or other asphalt is thrown in lumps inthe usual manner into the desiccating-vessel and closely envelops the central pipe 24. The heat from the furnace is communicated at once to the bottom of the vessel 4 and by conduction to the sides of said vessel and to its contents,

which gradually rise in temperature. The valves 24 and 12 being opened, a current of air under pressure enters through the pipe 23,- and passing downwardly through the pipe 24 to the branches 26 passes out through the openings therein. 0n escaping through the openings and at the hottest portion of the desiccatingwessell the condensed air immediately expands and passes upward in streams through the superjacent material, giving up its heat thereto and causing the material'to f give up at first a large amount of watery vapor, which issues, ytogether with 'the air, through the pipes 8 10 into thel condenser and separator 1l. XVith the watery vapor are also carried o some of the lighter asphaltum oils, partly in the form of condcnsable vapors and partly as uncondensable gases. The latter pass through the pipes 14,- 15, and 22 into the furnace-space, where they are consumed. The watery vapor and oily vapors -are condensed and pass by the pipes 17 and 10 to the common receptacle 20, where they separate by gravity, the oil floating ou the top of the water. The operation thus begun is continued until watery vapor is no longer given off from the desiccating-vcssel and until the charge is completely melted. As thescharge melts, the liquefied portion cores vor submerges the branch pipes 26, and the air as it .escapes bubbles up with expansive energy through the liquid, maintaining it in vigorous agitation. The unrestrained constant circulation thus induced disseminates the heat with great uniformity throughout the mass and enables me to employ a low temperature of from 250 to 300 Fahrenheit to effect the entire desiccation and at the same time to complete the operation in a much shorter period of time than with the higher heats heretofore employed. The heat conductivity of the pipe 25 isalso an important factor in shortening the time of treatment, for the reason that it melts the asphaltum immediately contiguous to its'walls, thereby permitting the heated air to rise in increased volume through the center of the charge and preventing the formation of a core. By the aid of, a suitable pyrometer care must be taken to maintain the temperature in the desiccating-vesscl at the low minimum indicated.' In practice I have found that a temperature of 250- Fahrenheit suced for the complete elimination of the watery vapor and the full melting of the charge. This temperature isy ordinarily maintained for about two days and a half, during which period a considerable quantity of asphaltum-oil isl obtained. At the end of said period this oil is restored to the purified asphaltum, either in complete substitution for the crude petroleum ordinarilyvemployed or in partial substitution therefor should au in `the purified asphalt is far superior to that v ture of 300 Fahrenheit, whereupon the de' l 435,198 l s of the crude petroleum, in some instances sired product is obtained. It will be understood that before adding the asphaltum oil in this last stage of the operation I preferably separate from it,by filtration, deposition, or otherwise, any objectionable foreign matters that may be present in it, such as soot, tar, Water, or the like.

Having thus described Ymy invention, what l. The process of refining crude asphaltum and obtaining an improvedv product therefrom, which consists in desiccating thecrude asphaltum at a low temperature, recovering the condensable oils given of during`desiccation, and subsequently returning said oils to vthe desiccated material, substantially as described.

2. Theprocess of refining crude asphaltu m,

which consists in simultaneously'desiccatin g and melting the same by subjectingit to heat until melted and simultaneously removing` the water by passing through the charge a current of air during the melting operation, substantially'as described.

3. 'lhe process of refining crudo asphaltum, which consists in subjecting the same to a temperature Aof from 250 to 300,I Fahrenheit and simultaneously passing through itacurrent of air, said air being admitted'at or near 4o the bottom or hottest portion of the charge, whereby it is suddenly expanded, substan tially as described.

4. As a new composition of matter, desiccated asphaltum containing in vsolution the condensable asphaltum oils given off during desiccation, substantially as described.

5. In the refining of cru'de asphaltum, the

process of preventing the formation Vof an unreduced central core within the refiningvessel,which consists in vadmitting air at or near the bottom of the charge and locating a portion of the air-inlet pipe'wit-hin the-center of the charge, whereby the charge surrounding said pipe is melted by conduction therefrom, thereby facilitating the passage of the air upward through thev said central portion, so as to rapidly liquefy it, substantially as described.

l x n In testimony whereof I affix my signature in `6o presenceof two witnesses.

ROBERT ALEXANDER..

lWitnesses: I

D. G. STUART, JOHN C. PENNIE. 

